1. Field of the Invention
This invention relates to an optical disc drive apparatus having a tilt correcting mechanism.
2. Description of the Related Art
An optical disc drive apparatus records and reproduces information on and from an optical disc. The optical disc drive apparatus includes an optical pickup head applying a laser light beam to the information recording surface of the optical disc. It is desirable that the direction of the applied laser light beam is perpendicular to the information recording surface of the optical disc. It should be noted that the laser light beam is also referred to as the laser beam.
In general, optical discs tend to be deformed from their original shapes by various causes. Such deformation of an optical disc adversely affects the perpendicularity between the direction of an applied laser beam and the information recording surface of the optical disc. It is known to provide an optical disc drive apparatus with a tilt correcting mechanism to maintain the perpendicularity between the direction of an applied laser beam and the information recording surface of an optical disc even when the optical disc is deformed from its original shape.
Japanese published unexamined patent application 2-94115 discloses a tilt correcting mechanism in an optical disc drive apparatus. As will be explained later, the tilt correcting mechanism of Japanese application 2-94115 has problems which cause reductions in accuracy of tilt correction.